This invention relates to drill bits.
Drill bits are known which utilise diamond or a diamond material as the cutting point. One example of such a drill bit utilises a cemented carbide insert located in a slot in the working end of a drill bit, the insert having a cutting edge of polycrystalline diamond.
CVD diamond is diamond produced by chemical vapour deposition. Chemical vapour deposition of diamond is well established and described extensively in the patent and other literature. Broadly speaking, the method involves providing a mixture of hydrogen or oxygen gas and a suitable gaseous carbon compound such as a hydrocarbon, applying sufficient energy to that gas to dissociate the hydrogen or oxygen into atomic hydrogen or oxygen, and the gas into active carbon ions, atoms or CH radicals, and allowing such species to deposit on a substrate to form diamond. Dissociation of the gases can take place by use of a hot filament or microwave or RF energy.